This application claims priority to WO 03/00538, filed Jul. 6, 2002 and KR11-0432244, filed Jul. 6, 2001.
The present invention relates to an iron core type linear motor, and more particularly to an iron core type linear motor with an improved cooling system for an easy manufacture thereof while having a high cooling efficiency.
An example of a conventional linear motor is disclosed in U.S. Pat. No. 5,850,112 (related to a heat release structure of such a linear motor). The disclosed linear motor includes a fluid cooling system including a primary cooling circuit and a secondary cooling plate arranged above a heat generating part of the linear motor, that is, a core, to prevent heat generated from the linear motor from being externally transferred, and an air cooling system including heat radiating fins surrounding a moving part of the linear motor to prevent residual heat from being externally radiated.
However, the above mentioned technique has various problems as follows.
First, the secondary cooling plate of the fluid cooling system is made of a flat metal plate formed with a circulating path for a cooling fluid in accordance with a drilling or boring process. However, where a plurality of elongated horizontal holes are formed through the flat metal plate in accordance with a drilling or boring process, the tip of the machining tool used in the machining process may be broken during the machining process due to the features of the machining process. Otherwise, the machining device used in the machining process may be damaged due to an increased load applied to the spindle of the machining device.
Second, adjacent ones of the elongated holes in the second cooling plate are connected to each other at their ends by connecting members, in order to allow circulation of a cooling fluid. For this reason, the manufacturing and installation costs are increased.
Third, the air cooling system is configured to prevent convection and radiation heat generated from the core from being externally transferred by use of heat radiating fins. However, this structure can cut off only the radiation heat directly transferred to external equipment through the heat radiating fins. For this reason, it is impossible to reduce the amount of heat emitted from the surface of the moving part. The heat emitted from the surface of the moving part heats the air surrounding the linear motor, thereby causing the linear motor to be heated. As a result, the linear motor may operate erroneously or exhibit a degradation in efficiency. Furthermore, the provision of the heat radiating fins causes an increase in the size of the linear motor. For this reason, this linear motor exhibits low utility.
The present invention provides an iron core type linear motor comprising a moving part including a core, coils, and an upper plate, and a stator including magnets, and a magnet fixing plate, further comprising:
a cooling system including a lower cooling conduit, a thermal insulating plate, and an upper cooling conduit laminated over one another in this order between the core and the upper plate.
In accordance with the present invention, the linear motor with the above described cooling system is characterized by heat shield plates respectively arranged at opposite side surfaces of the moving part to prevent heat from being transferred to the side surfaces of the moving part.
In accordance with the configuration according to the present invention, it is possible to efficiently prevent heat generated from the linear motor from being transferred to the surroundings, and to easily manufacture the linear motor using a simple assembly process.